Computerised tomographic images of holotype shells of Ennea serrata d’Ailly, 1896 (A–E SMNH Type-956) and E. nigeriensis sp. n. (F–J RMNH.MOL. 341194). A, F external shell in frontal view B, G internal shell in frontal view C, H internal view of body whorl, showing columella, angular lamella, and palatal fold(s) (indicated by arrow) D, I view of body whorl ceiling, showing course of angular lamella E–J ad-apertural view in body whorl, showing course of angular lamella. Holotype shells are of different dimensions but are scaled to approximately the same size here.